Electrosurgical device for restricting loss of blood during surgery

ABSTRACT

A device for restricting the loss of blood during a surgical procedure is disclosed. The device generates localized heating in an organ or volume of tissue and includes an applicator that is positioned against an organ or tissue to be treated, an array of retractable needles that deliver irradiating energy in the vicinity of a selected incision point; a switching mechanism in communication with the needles for energizing and causing movement of the needles and a power unit for supplying irradiating power to the needles when extended into the organ or tissue.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 11/055,858, filed Feb. 11, 2005, which is a divisional of U.S. patent application Ser. No. 10/625,232, filed Jul. 22, 2003, which is a continuation of U.S. patent application Ser. No. 09/762,285, filed Apr. 6, 2001, now U.S. Pat. No. 6,628,990, which is a national stage application of International Patent Application No. PCT/GB99/02559, filed Aug. 4, 1999, which claims priority from GB Patent Application No. 9817078.0, filed Aug. 5, 1998.

FIELD OF THE INVENTION

This invention relates to a device for use in the surgical treatment of human or non-human animals. In particular, it is concerned with a device for use in controlling excessive bleeding from severed tissue during surgical procedures, especially on the patient's liver.

BACKGROUND OF THE INVENTION

It is well known that raising the temperature of body tissue tends to reduce blood flow within the tissue. If the temperature is raised by 20-30° C. above normal, blood flow within the tissue is greatly diminished.

In surgical procedures performed on deep-seated body tissues and organs, e.g. the liver, blood loss from severed tissue can be a serious problem. There is an obvious need for a device which can assist in limiting such blood loss and, as indicated above, this can be achieved by means of the application of heat. Widespread heating can be achieved relatively easily, but this is not desirable. Very localised heating is required in order to minimize damage to surrounding tissues. In liver surgery, local heating of the liver is ideally required in a tissue volume approximately 5 cm long by 2 cm wide by 4 cm deep; this volume is centered on the planned point of incision. Furthermore, it is important for the local elevation of temperature to be achieved quickly just prior to commencing the surgical procedure.

SUMMARY OF THE INVENTION

The present invention aims to provide a device for providing localised heating of a selected region of body tissue prior to surgical incision of that tissue.

According to one aspect of the present invention, there is provided a device for generating localised heating in a selected body tissue, which device comprises an applicator including a source of microwave radiation and an array of retractable needles arranged so as to extend from one face of the applicator and, in operation, to confine the irradiated microwave energy field emanating from the applicator.

The invention also provides the use of the device as defined above for restricting the loss of blood during a surgical procedure on the human or animal body.

According to another aspect of the present invention, there is provided, in the surgical treatment of the human or animal body, a method of controlling excessive bleeding, the method comprising inserting an array of needles into the tissue or organ being treated; and applying microwave energy to the region undergoing treatment for a time sufficient to raise the temperature of said tissue or organ by 20-30 degrees C.

Conveniently, the source of microwave radiation is in the form of a rectangular waveguide whose dimensions correspond to those of the tissue volume which is to be heated. The waveguide is preferably generally rectangular in form, the array of retractable needles being positioned around the periphery of the waveguide.

The device may include a needle advance mechanism including a collar to which the needles are secured; movement of said collar may be actuated by a solenoid mechanism.

In operation of the device, the needles will be advanced from the body of the applicator into the tissue which is to be heated so that the needles function as a extension of the waveguide; in this way, the applicator will direct the required microwave energy into the appropriate tissue volume prior to surgery. When the heating process is completed, the needles are retracted back into the body of the applicator.

Generally, the needles will be disposed mutually parallel; they can conveniently be formed of steel.

Theoretical calculations show that, in order to raise the temperature of body tissues by 30° C., an applicator operating with 100% efficiency would need to deliver about 10 watts of microwave power, assuming that the volume to be heated is 40 cm³. For a typical biological tissue such as muscle, this temperature rise would be achieved in approximately 10 minutes. If the source is increased in energy to 500 watt, and if the applicator is assumed to be about 80% efficient, the time taken to achieve this required temperature increase is approximately 15 seconds.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:

FIG. 1 is a schematic representation of an applicator in accordance with this invention;

FIG. 2 is a cross-sectional view of the applicator head of FIG. 1;

FIG. 3 is an end elevational view corresponding to FIGS. 1 and 2.

DETAILED DESCRIPTION

Referring now to the drawings, a power and control unit (1) supplies up to 500 watts of microwave power via a coaxial cable (2) to a rectangular applicator (3). The head (3) has a handle (4) through which cable (2) passes, and an array (5) of retractable needles which are designed to provide precise irradiation of the tissue in the vicinity of the selected incision point. The unit (1) also contains a switching mechanism and control electronics to energise and release the array of needles.

As shown in FIGS. 2 and 3, the applicator head (3) includes a rectangular waveguide (6) around the periphery of which the needles of array (5) are located. The waveguide is a TM₁₁ mode waveguide and is filled with a suitable dielectric. For irradiation of a region 5 cm long by 2 cm wide, the rectangular waveguide should have corresponding dimensions and may be filled with a medium whose dielectric constant (∈_(x)) is about 50. These parameters dictate that the microwave operating frequency should be of the order of 1 GHz. The specific values given here are by of example only; it will be appreciated that a range of applicators designed to irradiate different volumes of tissue may be developed and these, of necessity, will have different dimensions and may require a different dielectric medium and a different operating frequency from that given above. In the illustrated embodiment, each of the needles is 3 cm long and made of steel. When the applicator is in operation, these needles will be advanced into the tissue where they function as an extension to the waveguide. A typical needle array may comprise about 20 needles. By employing a TM mode waveguide, leakage of energy through the “needle wall”—i.e., the area bounded by the array of needles—is kept to a low level (typically less than 10%).

FIG. 2 also shows a collar (8) to which each of the needles of the array (5) are secured. Collar (8) is acted upon by spring (9) which forms part of a solenoid mechanism (10) for controlling the advance and retraction of the array of needles. Power is supplied to the solenoid mechanism (10) via cable (11). As illustrated in FIG. 2, coaxial line (2) terminates within the dielectric-filled waveguide (6).

In operation, a surgeon will position the applicator head (3) against the region of tissue (e.g. liver) which is about to be incised. Initially the needle array (5) is retracted within head (3). When the applicator is actuated, solenoid mechanism (10) causes the needles of array (5) to be extended into the patient's tissue. Once they are embedded in the tissue, microwave energy at the desired frequency (e.g. 1 GHz) is supplied to waveguide (6) and passes therefrom into the volume of tissue enclosed by the array (5) of needles. Energy is supplied at a typical power level of 500 watts for a duration of about 15 secs when an applicator of the dimensions 5 cm×2 cm and a needle length of 3 cm is used. At the end of the treatment period, the microwave source is switched off and needle array (5) is retracted. The surgeon may then proceed with the incision and any subsequent procedures as may be necessary.

Blood loss from incision of tissue after heat treatment as described is greatly reduced in comparison to the results obtained in the absence of such heat treatment. 

1. A device for controlling excessive bleeding from severed tissue during a surgical procedure comprising: (i) an applicator; and (ii) a plurality of rows of tissue-piercing needles connected to and arranged on said applicator in a rectangular pattern wherein at least two of said plurality of rows define a central channel structured and arranged to be centered on a selected incision line such that one of said at least two rows of tissue-piercing needles is on the opposite side of said selected incision line from the second of said at least two rows of tissue-piercing needles, said plurality of rows of needles defining a three-dimensional space that corresponds to a volume of tissue to be treated; wherein said plurality of rows of needles are structured and arranged to be energizeable together, with needles in a plurality of said plurality of rows structured and arranged to be energized simultaneously to deliver ablating energy between, among and across said at least two of said plurality of rows of needles defining said central channel resulting in a cross-flow of energy into said volume of tissue to coagulate blood within the volume of tissue.
 2. The device as claimed in claim 1, wherein said plurality of, rows of needles are retractable.
 3. The device as claimed in claim 2 further comprising a needle switching mechanism for advancing and retracting said plurality of rows of needles.
 4. The device of claim 3 wherein said needle switching mechanism comprises a collar affixed to each needle comprising said plurality of rows of needles.
 5. The device of claim 4 wherein said needle switching mechanism further comprises a solenoid acting on said collar
 6. The device of claim 1 wherein said plurality of rows of needles are positioned around the perimeter of said applicator.
 7. The device of claim 1 wherein said ablating energy is electromagnetic energy.
 8. The device of claim 1 wherein said applicator defines a TM11 mode waveguide.
 9. The device of claim 7 wherein said applicator further comprises dielectric material.
 10. A device for supplying localized heating to an organ, part of an organ, or tissue along a defined incision line to minimize the loss of blood during resection, said device comprising: (i) an applicator; and (ii) at least two rows of needles connected to and arranged on said applicator in a rectangular pattern wherein said at least two rows of needles define a central channel structured and arranged to be centered on a defined incision line such that said at least two rows of needles straddle said defined incision line; said at least two rows of needles structured and arranged to be energizable together, with needles in said at least two rows of needles energized simultaneously, so as to supply three-dimensional ablating energy among and across said at least two rows of needles defining a central channel resulting in a cross-flow of energy into said volume of organ, part of organ, or tissue to coagulate blood within the volume of organ, part of organ, or tissue along said defined incision line.
 11. The device as claimed in claim 10, wherein said at least two rows of needles are retractable.
 12. The device as claimed in claim 11 further comprising a needle switching mechanism for advancing and retracting said at least two rows of needles.
 13. The device of claim 12 wherein said needle switching mechanism comprises a collar affixed to each needle comprising said at least two rows of needles.
 14. The device of claim 13 wherein said needle switching mechanism further comprises a solenoid acting on said collar
 15. The device of claim 10 wherein said at least two rows of needles are positioned at the periphery of said applicator.
 16. The device of claim 10 wherein said ablating energy is electromagnetic energy.
 17. The device of claim 16 wherein said ablating energy is microwave energy.
 18. The device of claim 10 wherein said applicator defines a TM11 mode waveguide.
 19. The device of claim 17 wherein said applicator further comprises dielectric material.
 20. A device for restricting the loss of blood during a surgical procedure comprising: (i) an applicator having a face for positioning against an organ or tissue to be treated, said applicator including a collar; (ii) an array of retractable needles secured to said collar and extending from said face, said array of retractable needles capable of irradiating said organ or tissue to be treated in a vicinity of a selected incision point; (iii) a solenoid mechanism in communication with said array of retractable needles for energizing and releasing said array of retractable needles; and (iv) a power unit in communication with said array of retractable needles for supplying irradiating power to said needles when extended into said organ or tissue in the vicinity of the selected incision point.
 21. The device of claim 20 wherein the power unit supplies sufficient power for a period required to raise the temperature of said organ or tissue in the vicinity of the selected incision point by about 20° C. to about 30° C.
 22. The device of claim 20 wherein said array of retractable needles provide local heating of the organ or tissue within a volume approximately 5 cm long, 2 cm wide and 4 cm deep.
 23. A device for controlling excessive bleeding from severed tissue during a surgical procedure comprising an applicator including a plurality of needles connected to a solenoid-activated collar affixed to each of said plurality of needles for advancing and retracting said plurality of needles, each said needle having a first end and a second end, said second end structured to pierce said tissue along a selected incision line; wherein said plurality of needles are energizeable to deliver ablating energy to said tissue along said selected incision line.
 24. The device of claim 23 wherein said plurality of needles when extended define a volume whose dimensions correspond to the tissue volume to be ablated.
 25. The device of claim 23 wherein said plurality of needles are positioned around the perimeter of said applicator.
 26. The device of claim 23 wherein said ablating energy is electromagnetic energy.
 27. The device of claim 23 wherein said applicator defines a TM11 mode waveguide.
 28. The device of claim 27 wherein said applicator further comprises dielectric material.
 29. The device of claim 1 wherein said applicator is structured to be operably coupled to a source of said ablating energy.
 30. The device of claim 1 wherein said plurality of rows of tissue-piercing needles comprises two rows of needles.
 31. The device of claim 1 wherein said plurality of rows of tissue-piercing needles comprises four rows of two needles each arranged around a perimeter of said applicator.
 32. The device of claim 35, wherein each needle includes a tissue-penetrating shaft that is sleeveless and non-insulated along the entire portion of the shaft that extends from the applicator body and said irradiating power is supplied along the length of the sleeveless, non-insulated tissue-penetrating shaft when extended into said organ, part of organ, or tissue.
 33. The device of claim 1 wherein each needle comprising said plurality of rows of tissue-piercing needles include a tissue-penetrating shaft that is sleeveless and non-insulated along the entire portion of the shaft that extends from the applicator body and said ablating energy is delivered into said volume of tissue along the length of the sleeveless, non-insulated tissue-penetrating shaft.
 34. The device of claim 10 wherein each needle comprising said at least two rows of needles include a tissue-penetrating shaft that is non-insulated along the entire portion of the shaft that extends from the applicator body to the tip and said energy is delivered into said volume of tissue along the length of the non-insulated tissue-penetrating shaft.
 35. A device for controlling excessive bleeding from severed tissue during resection comprising: (i) an applicator; and (ii) four tissue-piercing needles connected to and arranged said applicator in a pattern of two rows by two columns that define a central channel structured and arranged such that at least two of said four tissue-piercing needles are arranged to be positioned on one side of a width of tissue and at least two of said four tissue-piercing needles are arranged to be positioned on an opposite side of said width of tissue, said width of tissue defining a planned incision line corresponding with said channel, said four tissue-piercing needles structured and arranged to be energizeable together to deliver three-dimensional energy among and with a cross-flow across said plurality of tissue-piercing needles and into a volume of tissue defined by said width along the planned incision line.
 36. The device as claimed in claim 35, wherein said needles are retractable.
 37. The device as claimed in claim 36 further comprising a needle switching mechanism for advancing and retracting said needles.
 38. The device of claim 37 wherein said needle switching mechanism comprises a collar affixed to each needle.
 39. The device of claim 38 wherein said needle switching mechanism further comprises a solenoid acting on said collar
 40. The device of claim 35 wherein said ablating energy is electromagnetic energy.
 41. The device of claim 35 wherein said applicator defines a TM11 mode waveguide.
 42. The device of claim 35 wherein said applicator further comprises dielectric material.
 43. The device of claim 35 wherein said needles are positioned around the periphery of said applicator.
 44. The device of claim 35 wherein said ablating energy is microwave energy.
 45. The device of claim 35 wherein said rows of needles are parallel to each other and said columns of needles are parallel to each other.
 46. The device of claim 1 wherein said rectangular pattern of needles comprises four needles arranged in a two by two array.
 47. The device of claim 10 wherein said rectangular pattern of needles comprises an array of four needles disposed in a two by two array.
 48. A device structured to bloodlessly resect tissue during a surgical procedure comprising: (iii) an applicator; and (iv) four tissue-piercing needles connected to and arranged about a perimeter of said applicator in a rectangular pattern of two by two needles each, said pattern defining a central channel structured and arranged to be positioned on a selected incision line such that one of said rows of tissue-piercing needles is on the opposite side of said selected incision line from the second of said row of tissue-piercing needles, said two rows of needles defining a three-dimensional space that corresponds to a volume of tissue to be treated; wherein said two rows of needles are structured and arranged to be energizeable together and simultaneously to deliver ablating energy between, among and across said four needles resulting in a cross-flow of energy into said volume of tissue to coagulate blood within the volume of tissue.
 49. A device structured to bloodlessly resect tissue during a surgical procedure consisting essentially of: (i) an applicator; and (ii) four tissue-piercing needles connected to and arranged about a perimeter of said applicator in a rectangular pattern of two by two needles each, said pattern defining a central channel structured and arranged to be positioned on a selected incision line such that one of said rows of tissue-piercing needles is on the opposite side of said selected incision line from the second of said row of tissue-piercing needles, said two rows of needles defining a three-dimensional space that corresponds to a volume of tissue to be treated; wherein said four needles contained within said two rows are structured and arranged to be energizeable together and simultaneously to deliver ablating energy between, among and across said four needles resulting in a cross-flow of energy into said volume of tissue to coagulate blood within the volume of tissue. 